Internal-combustion engine



1,616,941 1927' L. M. WOOLSON INTERNAL COMBUSTION. ENG INE Filed Jan.14, 1925 E E gone! m. MOOISOR Patented. Feb. i927.

earner LIONEL M. WOOLSON, F DETROIT, MICHIGAN, ASSIGNOR T0 PACKARD MOTORCAR COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

INTERNAL-COMBUSTION ENGINE.

Application filed January This invention relates to internal combustionengines, more particularly to the cooling systems thereof and it has forone of its objects to provide a cooling system in which the weight offluid necessary to cool the engine shall be much reduced and the ratioof engine weight to power developed shall be thereby decreased.

Another object of the invention is to provide an engine cooling'systemfor use on motorvehicles in which the head resistance caused by theradiator shall be materially reduced.

, A further object of the invention is to provide an engine coolingsystem having cooling jackets or spaces surrounding the engine cylindersin which the surfaces of the jacket and the cylinder barrel shall beprotected from rust and other corrosion.

- Other objects of the invention will appear from the followingdescription taken in connection with the drawings, which form a part ofthis specification, and in which:

Fig; 1 is a view in side elevation, partially broken away and partiallyin section, of a portion of an internal combustion engine illustratingthe invention, and

Fig. 2 is an enlarged sectional view of a %ortion of the engine shown inFig. 1.

3o efinement in the design of water-cooled internal combustion engineshas progressed to a. point where the weight of the cooling systemcarried is a material factor in the ratio of engine weight to poweroutput.

Particularly is this true in engines such as are used in the propulsionof aircraft; such engines having "been built in which the weight is'aslow as 1.5 to 1.7 pounds per brake horsepower developed, but-in which 40the weight of the radiator and cooling water carried is 35 percent to 40percent of the total engine weight. Ordinarily, the temperature at whichthe cylinder walls of an engine may be operated is limited by theboiling temperature of water at the atmos pheric pressures encountered,and-"sufficient water must be carried with a given'rate of circulationto maintain the cylinder wall temperature below this point under allpower "outputs, since it is essential that. no appreciable loss of waterby evaporation shall occur. The weight of cooling water which'must becarried by an engine of given size is thus approximately fixed.

14, 1 92l5. Serial No. 2,276.

preventing loss from evaporation. This result is accomplished byretarding the transfer of heat from the cylinder walls to the coolingwater which is circulated around them, so that less heat is absorbed bythe water. Preferably the cylinder walls are given a thin film orcoating of any suitable heat retarding material, byrwhich the flow ofheat through the cylinder walls to the cooling space is checked. In thisway not only is the weight of cooling water reduced,

butthe size of radiator required may be also reduced in proportion, thusdecreasing both the weight and the wind resistance of the vehicle whichis being driven. This last named feature is particularly valuable inaeronautics in which the parasitic resistance overcome represents theexpenditure of a large proportion of the total power.

Referring to the drawings, at 10 is shown a portion of an internalcombustion engine having a crankcase 11 on which is mounted a bank 12 ofcylinders 13. As shown, the bank of cylinders 12 is formed as anintegral cylinder block, but it is to be understood that the bankmay-consist, if desired, of individual cylinders, separately secured tothe crankcase, or in groups of cylinders of any desired number, as iswell understood in the art to which this invention relates. Thecrankcase 11 is provided with suitable bear ings 14, in which isjournaled a crankshaft 15, and this crankshaft is connected byconnecting rods 16 to pistons 17, adapted to reciprocate in thecylinders 13 in the usual manner.

The cylinders 13 are provided with a suitable head, which in theembodiment illustrated comprises an integral head casting 18, providedwith a combustion chamber 19 for each of the cylinders 13, and providedwith suitable passages 21 for the circulation of cooling water; thepassages 21 forming a water jacket for the cylinder head.- Each of thecylinders 13 is also provided with a cooling space 22 formed in thecylinder block 12 to surround the cylinder, and constituting a waterjacket therefor, these jackets being connected in any suitable manner,not shown. If separate cylinders are employed, each of these cylinderswill have an independent water jacket, as will be readily understood.Suitably mounted in a housing engine 10, preferably at the forward endof the cylinder block 12, is a water pump 23, adapted to maintain aforced circulation -of cooling water through the jackets 21 and 22 as isreadily understood. The pump 23 may be of any suitable type but ispreferably of the rotary type, having a shaft 24, driven by a pulley 25and a belt 26 from any convenient rotating. part of the engine, such asthe engine camshaft (not shown).

Mounted forwardly of the engine 10 is the usual radiator 27, having atitsazpper end an inlet 28 for heated water from the water jacket 21, andat its lower end. an outlet 29, connected by suitable means, such as theconduit 31, with the intake of the pump 23. The radiator 27 has a coreportion comprising air passages or tubes 32 extending from front torear, around which the water in the radiator flows as it moves from theupper to the lower portionof the radiator, being cooled in the process,as is well understood. The forward end of the pump shaft 24 ispreferably provided with a fan 33 by which the natural draught of airthrough the tubes 32 is augmented. The radiator inlet 28 is connected byany suitable conduit 34 with a jacket outlet 35, formed on the cylinderhead block 18 and communicating with the water jacket 21.

The circulation of water through the cooling system described is wellknown. Water from the delivery side of the pump 23 en- .ters a suitabledistributing conduit (not shown) by means of which it is introduced intothe various cylinder cooling jackets 22,

through which it flows in parallel, absorbing heat from the cylinderwall. The heated water rises and enters the cylinder head jacket 21,absorbingheat from the cylinder wallsand particularly from thecombustion chambers 19, and flows forwardly into the outlet 35, throughconduit 34and radiator inlet 28 into the upper end of the radiator 27.Here it is subjected to the cooling ac tion of the air passing throughthe tubes 32. The cooled water is drawn from the bottom of the radiatorthrough the outlet 29 and passes through the conduit 31 into the intakeof the pump 23, thus completing the cycle.

As previously explained, the volume and hence the weight of coolingwater which is necessarily carried by the engine is practicallyestablished for any given maximum power output of the engine. Thisvolume must be suflicient to absorb the heat gener ated at such poweroutput without exceeding the boiling temperature of water. In thepresent invention the quantity of water carried is decreased, and thetemperature of the walls of the cylinders 13 is correspondinglyincreased by retarding the transfer of heat from the cylinders 13 to thecooling water in the jackets 21 and 22. To accomplish this the walls ofthe cooling spaces are coated with a thin film of heat resisting orinsulating material so that the transfer of heat therethrough takesplace at a much less rapid rate. Any suitable material may be used forthis purpose but it has been found that certain of the phenolcondensation products, such as the well known bakelite, provide a verysatisfactory coating. This material is heat resistant, is waterproof,and may be repeatedly wetted and dried without cracking or otherdeterioration.

This material may be applied to the cylinder jackets in any suitableWay. In engines having independent cylinders, in which the coolingjackets are affixed to the cylinder walls after manufacture thereof, thebakelite insulation may be applied to the inner walls of the cylindersin the form of thin sheets before attachment of the cooling jackets tothe cylinder forgings, or it may be mouldedin place. In engines cast enbloc, as in the embodiment disclosed herein, the insulating film may beconveniently applied in the form of a varnish. In this method ofapplication the cooling spaces of the engine are filled with such avarnish which is allowed to stand a short time, and are then drained.Drying of the varnish fihn thus applied to the walls of the coolingjackets may be hastened by a draught of air from any suitable source,introduced through the pump intake and exhausting through the jacketoutlet .35. After a coating of such varnish has been suitably dried,another coat may be applied in a similar manner until an insulating film36 of sufficient thickness has been built up on the inner surfaces ofthe cooling spaces 21 and 22. This varnish may be prevented fromentering the pump chamber by blocking ofi the distributing conduitduring the filling and draining operations.

The varnish film 36 forms a shield between the walls of the cylinders 13and the combustion chambers 19, and the water in the cooling spaces 21and 22, which retards or checks the flow of heat into the cooling water.It is obvious that this will cause the cylinder Walls to rise to ahigher temperature, and that a smaller volume of "cooling water willmaintain the walls at this may therefore be materially reduced, and thisnot only greatly decreases the ratio of weight to horsepower of theengine but permits the use of a smaller radiator and thereby lowers thehead resistance of the vehicle on which the engine is mounted.

It, is also apparent that the varnish film 36 forms a protective coatingfor the interior of the cooling space, preventing rust and othercorrosion of the'metal of the cylinder walls. a

It will be understood that various forms of the invention other thanthose described above may be used without departing from the spirit .orscope of the invention.

What is claimed is: 1. The combination in an internal combustion engine,of a cylinder, having walls and a head, a jacket for said wallsand headdefining therewith a cooling space adapted to contain cooling fluid, anda thin covering for said walls and head within said space and imperviousto the cooling fluid to retard the transfer of heat from the cylinder tosaid fluid.

2. The combination with an engine having cylinders and a head, and ajacket surrounding the cylinders and head adapted to contain coolingfluid, of heat retarding varnish onthe inner walls of said jacketadapted to delay the transfer of heat from the cylinders and head to thecooling fluid.

3. The combination with an engine cylinder having a jacket defining acooling space,

cylinder and said cooling space, said means of heat retarding meansbetween the comprising a varnish containing a condensation product ofphenol.

4. The combination with an engine cylinder having walls and a jacketdefining a cooling space, of a thin coating of heat retarding Varnish onthe cylinder and jacket walls within the cooling space adapted to afiectthe flow of heat through said cylinder walls tosaid cooling space.

5. The combination in an int rnal combustion engine, of a cylinderhaving walls and a head surrounded by a cooling fluid,-

and a thin heat-retarding covering for said walls and head adapted toprevent corrosion by the cooling fluid.

6. The combination in an internal com.- bustion engine, of a cylinderhaving walls and a head, a jacket for said walls and head definingtherewith to contain cooling fluid, and a thin coating for said Wallsand head in contact with the cooling fluid and ada ted to resistcorrosion thereby, to retard t e flow of heat from said walls and headto said fluid.

7. The combination with an engine cyla cooling space adapted.

inder having a jacket defining a cooling v space, of cooling fluid insaid space to absorb heat from the walls of the cylinder, and a thincoating of heat retarding material on said walls in contact with saidfluid adapt- Ed is) prevent corrosion of said walls by said In testimonywhereof I aflix my signae ture.

" LIONEL M. WOOLSON.

